A conventional optical film as shown in FIG. 1 comprises: a base layer B, and a prismatic layer P having a plurality of prisms arranged side by side and integrally formed on the base layer B.
In order to enhance the on-axis brightness of such a conventional optical film, plural design variables should be considered, namely, the variable angles, the orientations of the prisms, the additional light guiding elements if required, and other design factors, thereby increasing the production complexity and cost.
The present inventor has found the drawbacks of the prior art and invented the present optical film for enhancing the on-axis brightness thereof.